coredns/middleware/metrics/README.md

# prometheus

This module enables prometheus metrics for CoreDNS. The default location for the metrics is
`localhost:9153`. The metrics path is fixed to `/metrics`.

The following metrics are exported:

* coredns_dns_request_count_total
* coredns_dns_request_duration_seconds
* coredns_dns_request_size_bytes
* coredns_dns_request_do_count_total
* coredns_dns_request_type_count_total
* coredns_dns_response_size_bytes
* coredns_dns_response_rcode_count_total

Each counter has a label `zone` which is the zonename used for the request/response. and a label
`qtype` which old the query type. The `dns_request_count_total` has extra labels: `proto` which
holds the transport of the response ("udp" or "tcp") and the address family of the transport (1
= IP (IP version 4), 2 = IP6 (IP version 6)). And `type_count_total` hold a per RR type counter, it
holds the most common ones (A, AAAA, MX, SOA, CNAME, PTR, TXT, NS, SRV, DS, DNSKEY, RRSIG, NSEC,
NSEC3) and "other" which lumps together all other types.

The `response_rcode_count_total` has an extra label `rcode` which holds the rcode of the response.
The `*_size_bytes` counters also hold the protocol in the `proto` label ("udp" or "tcp").

If monitoring is enabled queries that do not enter the middleware chain are exported under the fake
domain "dropped" (without a closing dot).

Restarting CoreDNS will stop the monitoring. This is a bug. Also [this upstream
Caddy bug](https://github.com/mholt/caddy/issues/675).

## Syntax

~~~
prometheus
~~~

For each zone that you want to see metrics for.

It optionally takes an address where the metrics are exported, the default
is `localhost:9153`. The metrics path is fixed to `/metrics`.

## Examples